In small saucepan, heat water to 120°. In large mixer bowl, combine 3 cups flour, yeast and salt. Add warm water and mix by hand or on medium speed of electric mixer for 3 minutes. Gradually add enough remaining flour to form a stiff dough. Turn dough out onto lightly floured board or pastry cloth; knead until smooth and satiny, about 8-10 minutes. Place dough in a greased bowl, turning once to grease top. Cover and let rise in a warm place 30 minutes. After it has risen, punch down and divide into 2 equal parts. Roll each half of dough into a 15x8 rectangle on a lightly floured board. Beginning with long side, roll dough up tightly, sealing edges and ends well. Place loaves seam side down, diagonally, on a lightly greased baking sheet that has been sprinkled with cornmeal. Brush loaves with oil, cover. Refrigerate 2-24 hours. When ready to bake, preheat oven to 400°F. Remove bread from refrigerator, uncover and let stand 20 minutes. Brush bread with water. Slash tops of loaves diagonally at 2-inch intervals just before baking. Bake at 400° for 35-40 minutes.